I don't remember. I think I first heard about this when I was traveling in New Zealand and Australia in a year off that I took from college. I would love to do this! I want to try it in Iceland. It is very health-promoting. I'd also like to bathe in The Dead Sea and, I'm not sure if this is a thing or not, but I'd like to go in a hot mud spring in a beautiful location somewhere in the big wide world. Christa Bergman Brown